Diversity and composition of tropical butterflies along an Afromontane agricultural gradient in the Jimma Highlands, Ethiopia

Afromontane landscapes are typically characterized by a mosaic of smallholder farms and the biodiversity impacts of these practices will vary in accordance to local management and landscape context. Here, we assess how tropical butterfly diversity is maintained across an agricultural landscape in the Jimma Highlands of Ethiopia. We used transect surveys to sample understory butterfly communities within degraded natural forest, semi-managed coffee forest (SMCF), exotic timber plantations, open woodland, croplands and pasture. Surveys were conducted in 29 one-hectare plots and repeated five times between January and June 2013. We found that natural forest supports higher butterfly diversity than all agricultural plots (measured with Hill's numbers). SMCF and timber plantations retain relatively high abundance and diversity, but these metrics drop off sharply in open woodland, cropland and pasture. SMCF and timber plantations share the majority of their species with natural forest and support an equivalent abundance of forest-dependent species, with no increase in widespread species. There was some incongruence in the responses of families and sub-families, notably that Lycaenidae are strongly associated with open woodland and pasture. Adult butterflies clearly utilize forested agricultural practices such as SMCF and timber plantations, but species diversity declines steeply with distance from natural forest suggesting that earlier life-stages may depend on host plants and/or microclimatic conditions that are lost under agricultural management. From a management perspective, the protection of natural forest remains a priority for tropical butterfly conservation, but understanding functioning of the wider landscape mosaic is important as SMCF and timber plantations may act as habitat corridors that facilitate movement between forest fragments

Arbuscular mycorrhizal fungi (AMF) root colonization dynamics of Molinia caerulea (L.) Moench. in grasslands and post-industrial sites

This is an accepted manuscript of an article published by Elsevier in Ecological Engineering on 05/08/2016, available online: https://doi-org.ezproxy.wlv.ac.uk/10.1016/j.ecoleng.2016.06.029 The accepted version of the publication may differ from the final published version.The aims of this studies were: (i) to examine the influence of heavy metal content (Zn, Cd, Pb, Fe, Cu) and other physico-chemical soil parameters on the level of root colonization of Molinia caerulea and (ii) to relate root colonisation parameters and soil variables to Molinia caerulea abundance in two contrasting habitats (grasslands and heavy metal contaminated sites). The sites differ significantly in terms of bio-available heavy metal contents, particularly Zn (34 times more than grasslands), soil texture, CaCO3, organic matter (LOI%), Mg and nitrate content. Principal Component Analysis showed the strong negative correlations between frequency of mycorrhization (F), arbuscular abundance (A%) and intensity of root cortex colonisation (M%) and concentration of bio-available Zn and Cd. Moreover, no positive correlation between root colonization of Molinia and its abundance was found. The frequency of mycorrhization of root fragments (F%) was only slightly different between these two habitats, whereas the intensity of root cortex colonisation (M%) and relative arbuscular abundance (A%) were significantly lower (3 and 4 times respectively) on the post-industrial sites. The bioavailable Zn content in the substratum of post-industrial sites was strongly negatively correlated with species richness, Shannon diversity index and Evenness. In contrast, these relationships were not statistically significant in grasslands. Based on obtained results we could draw a model of possible relationships between root colonization of Molinia, HM content and Molinia abundance on grasslands and post-industrial sites. Bioavailable Zn content in the soil is a one of main factors influencing the Molinia community diversity. In the grasslands, lower amounts of bioavailable Zn, resulted in higher species richness (R) and species diversity (H) which in turn lead to higher root colonization. On the other hand, on the post-industrial sites, the elevated bioavailable Zn content strongly decreases the plant species richness (R) and species diversity (H) and this caused the decline in root colonization parameters. The low species richness on Zn-polluted sites allowed Molinia to reach higher abundance since the competition with other species is reduced

Co-limitation towards lower latitudes shapes global forest diversity gradients

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers

Co-limitation towards lower latitudes shapes global forest diversity gradients

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers

Co-limitation towards lower latitudes shapes global forest diversity gradients

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers

Two groups of epigeic arthropods differ in colonising of piedmont quarries: the necessity of multi-taxa and life-history traits approaches in the monitoring studies

It is increasingly understood that inventorying and monitoring biodiversity requires a multi-taxon approach and that comparing simple indices, such as species richness, should be accompanied by deeper analyses of species community composition and by comparisons of species life-history traits among taxa and habitats. Here, we document that two ecologically rather similar groups of epigeic predators, ground-dwelling spiders (Araneae) and ground beetles (Coleoptera: Carabidae), differ in patterns of stone quarry colonization. Such post-industrial barrens as abandoned quarries are increasingly appreciated as potential refuges for species that are becoming rare in modern landscapes. We compared species richness, community composition and species life-history traits of two epigeic invertebrates groups, in quarries and adjoining seminatural biotopes in a submountain region with granulite and limestone bedrock in SW Czech Republic. For both groups, quarries were species-poorer than seminatural sites, herbaceous biotopes were richer than scrubby and rocky biotopes, and no significant effects on species richness were revealed for substrate. Assemblages colonising quarries differed from those outside of quarries. They contained numerous regionally rarer species of rocks and scree in the case of spiders, but generalists of open landscapes prevailed among ground beetles. A survey limited to ground beetles, as well as to species richness analyses, would fail to detect a conservation potential of the quarries. Hence, a multi-taxa approach should be preferred, and species richness analyses should be assembled by insights onto community composition and species life-history traits in monitoring studies